Electrical apparatus



Oct. 23, 1928. 1,688,737

w. s. MOODY ELECTRICAL APPARATUS Filed April 5; 1922 Inventor: Wa Iter' S. Moody.

WWM

H i s- Attiorn ey.

Patented Oct. 23, 1928.

UNITED STATES,

WALTERS. I OODY, OF PITTSEIELD, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC 1,688,737 PATENT OFFICE.

\ COMPANY, A. CORPORATION OENEW YORK.

ELECTRICAL APPARATUS.

Application filedpr'il 5,

apparatus which is cooled by immersion in a body of suitable liquid such as 011. The general object of the invention is to provlde an improved method whereby the level of the liquid within the casing enclosing the apparatus may be conveniently lowered to permit the casing to be opened when desirable as for purposes of inspection or repair.

In the-operation of transformers and other electricalinduction apparatus, the apparatus is commonly immersed in a suitable insulating and cooling liquid, such as oil, contained in a surrounding casing. It is generally desirable that the casing be completely: filled with liquid to exclude all air, thus avoiding contamination of the liquid by oxidation and preventing the formation of explosive mixtures of gases within the casing. The liquid necessarily expands and contracts under the influence of varying temperature imposed by variations of the load carried by the immersed apparatus and this expansion and contraction is commonly cared for by'an exgansion chamber orconservator partially lled with liquid and'connected with the casingwhich contains the'apparatus and the main body of liquid. I

It is at times necessary to open the casing of an immersed induction apparatus in order to inspect or repair the apparatus, and, in order not to spill and waste someof the liquid when the casingis opened, some of the liquid must be removed and its level in the casing lowered belowthe cover or other part of the casing which is removed. In accordance with this invention, the expansion chamber serves as a convenient auxiliary res ervoir or container for liquid thus removed from the casing. Another feature of the invention resides in means adap ed to cause the desired quantity of liquid to be transferred or ex elled from the casing to the expansion 1922. Serial No. 549,943.

showing conditions after the casing has been Like reference characters indicate similar parts in' both figures of the drawing.

The particular apparatus shown in the drawing includes a casing 1 containing a transformer 2 and filled with a suitable cooling and insulating liquid 3 such as oil. The liquid -3 extends through a pipe 4 into an expansion chamber or conservator 5 which is only partially filled as indicated by the level 6 of the liquid in this chamber and which permits thermal expansion and contraction of the liquid in the casing. A breather? leading to the outside air permits liquid to enter and leave the expansion chamber" 5 through the pipe 4.

.It is clear that before removing the cover of the casing 1 to reach the apparatus enclosed within the casing, it is. first necessary to remo've enough liquid from the casing to lower its level below or at least to the upper edge of the side wall'of the casing that is, to or below the openinin the top of the casing left by the removal 0 the cover. Otherwise, any llquid above the edge of the opening would spill out and be wasted. A blower or pump 8 is accordingly provided for forcin air or other gas'intothe casing 1 under su cient pressure to cause liquid to flow from the casing 1 into the expansion chamber 5. After opening. the

valve 9, liquidis thus transferred or expelled from the casing 1 to the expansionchamber 5 until the level of that left in the casingis below the upper ed e of the body of the casing as indicated in 1 2 of the drawing. The pipe 4 is connecte to the casing 1 at a point below the cover of the casingso that the gas which is forced into the casing cannot reach this pipe and pass into the expansion chamber. The expansion chamber is, of course, of s'uflicient capacity to hold the liquid thus transferred in addition to the amount chain r and storing it there during. such hi h it; normally o t i The valve 9 w and 10 are then'closed, after whic the cover time-asthe casing is open.

The invention will be described in connec [tion with the accompanying drawing in 'which Fig. 1 shows a particular embodiment thereof in which a casing enclosing a trans-:.

former immersed in a cooling liquid is equipped in accordance with the invention,

g n and Fig. 2 is a'partial view, on a reduced scale may be removed from the casing as shown in Fig; 2 without danger of spilling any liquid.

valve 10 and leaving a small openlng such as I may be provided by the valve 11 anywhere inthe top of the cover for. the escape of air or other gas from the casing, the liquid return 'ing from the expansion chamber 5 under the influence of gravity as the level of the liquid in the expansion chamber is higher than that of the liquid in the casing.

What I clairri as new and desire to secure by Letters Patent of the United States, is

1. The method of opening a casing filled with liquid in which electrical induction apparatus is immersed and having an expansion chamber containing liquid to a level higher than that in the casing, said expansion chamber communicating with the casing below the point at which the opening is to be made, whereby thermal expansion and contraction of the liquid is permitted, said method including the steps of causing liquid to be expelled from the easing into the expansion chamber to lower the level of the liquid within the casing below the opening to be made, preventing return of the expelled liquid, making an opening into the casing above the level of the liquid remaining 'there- 1 in, and subsequently closing said opening and permitting liquid to return by gravity from said expansion chamber to' refill said casing.

2. The method of Openinga easing filled with liquid in which electrical induction apparatus is immersed and having an expansion chamber containing liquid to a level higher than that in the casing, said expansion chamber communicating with the casing below the point at which the opening is to be made, whereby thermal expansion and contraction of the liquid is permitted, said method including the steps of transferring liquid from the casing to the expansion chamber by applying gas pressure to the liquid in the casing to lower the level of the liquid within the casing below the Opening to be made, preventing return of the transferred liquid, making an opening into the casing above the level of the liquid remaining therein, and subsequently closing said opening and permitting liquid to return by gravity from said expansion chamber to refill said casing.

In witness whereof, I have hereunto set my hand this 3rd day of April,'1922.

- WALTER S. MOODY. 

